Method for manufacturing an armature for a dynamo-electric machine

ABSTRACT

A method for manufacturing an armature including securing a core to the shaft having a plurality of slots extending in the axial direction formed on the outer circumferential surface thereof, forming a coil composed of a plurality of coil portions by simultaneously winding wires a plurality of turns around a pair of slots separated by a predetermined number of slots and offsetting each of the coil portions one slot at a time in the circumferential direction of the core, securing a commutator to the shaft having a plurality of segments, adjacent coil portions having a slot along one side thereof, wherein a number of vacant slots between adjacent ones of the coil portions within each of simultaneously-wound coil portion groups is nonuniform, and electronically connecting segments which should have the same electric potential by means of equalizing connectors so that each of pairs of the coil portions that should have the same electric potential has a substantially equal electric potential.

This is a divisional of application Ser. No. 10/834,242 filed Apr. 29,2004 U.S. Pat. No. 7,114,236, which is a divisional of application Ser.No. 09/987,374 filed Nov. 14, 2001 U.S. Pat. No. 6,844,649, which is acontinuation of application Ser. No. 09/266,606 filed Mar. 11, 1999(abandoned), the disclosures of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an armature for a dynamo-electricmachine in which side portions of adjacent coil portions, etc., share aslot.

2. Description of the Related Art

FIG. 11 is a side elevation of an armature 1 for a conventional motor.The armature 1 is disposed so as to be freely rotatable within a stator(not shown) having four poles. The armature 1 comprises: a motor shaft2; a core 3 secured to the motor shaft 2 having slots 4 extending in theaxial direction; a coil 6 composed of wires 5 coated with enamel woundaround the core 3; and a commutator 8 secured to the motor shaft 2 atone end of the core 3.

The commutator 8 has twenty-one segments 11; insulating segments 10electrically insulating the segments 11 from each other; and hooks 12disposed so as to protrude from each of the segments 11 which areelectrically connected to the wires 5.

FIG. 12 is a front elevation of the core 3. Twenty-one slots 4 areformed in the core 3 spaced equidistantly in the circumferentialdirection and teeth 9 are disposed between the slots 4. The coil 6 iscomposed of wires 5 wound onto the core by so-called “lap winding”.

FIGS. 13 to 15 are diagrams explaining the winding of the wires 5 ontothe core 3 by the lap winding method.

FIG. 13 is a diagram showing the wires 5 being simultaneously suppliedfrom the nozzles of a winding device (not shown) which winds the wires 5onto the core 3, simultaneously forming a first coil portion A 30, afirst coil portion B 31, and a first coil portion C 32, respectively.The first coil portion A 30 is formed by winding a wire 5 supplied froma first nozzle, for example, ten or so turns around tooth No. 2 of theteeth 9 and tooth No. 6 of the teeth 9 which are separated by four slots4. The first coil portion B 31 is formed by winding a wire 5 suppliedfrom a second nozzle, for example, ten or so turns around tooth No. 9 ofthe teeth 9 and tooth No. 13 of the teeth 9 which are separated by fourslots 4. The first coil portion C 32 is formed by winding a wire 5supplied from a third nozzle, for example, ten or so turns around toothNo. 16 of the teeth 9 and tooth No. 20 of the teeth 9 which areseparated by four slots 4.

FIG. 14 is a diagram showing wires 5 continuing to be supplied from thenozzles of the winding device (not shown) after engaging the hooks 12,additionally forming a second coil portion A 36, a second coil portion B37, and a second coil portion C 38, respectively.

FIG. 15 is a diagram showing the completed winding of the wires 5between the teeth 9 of the core 3. A third coil portion A 42, a fourthcoil portion A 45, a fifth coil portion A 48, a sixth coil portion A 51,and a seventh coil portion A 54 are additionally and continuously formedby the wire 5 supplied from the first nozzle. A third coil portion B 43,a fourth coil portion B 46, a fifth coil portion B 49, a sixth coilportion B 52, and a seventh coil portion B 55 are additionally andcontinuously formed by the wire 5 supplied from the second nozzle.

In the above motor, the armature 1 is rotated about the motor shaft 2 byelectromagnetic action by supplying an electric current to the coil 6from outside by means of brushes (not shown) which contact the segments11. The segments 11 contacted by the brushes are switched in succession,switching the direction of the current supplied to the coil 6, so thatwhatever rotational position the armature 1 is in, the rotating force onthe armature 1 is in a specific direction.

In the conventional (but not prior art) armature 1 described above,there are twenty-one slots 4 in total and three nozzles, the totalnumber of slots 4 being evenly divisible by the number of nozzles, andthe wires 5 are wound uniformly in each of the coil portions, making theimpedance substantially the same in adjacent coils portions.

However, if, for example, the number of slots is increased fromtwenty-one to twenty-two in order to increase torque, and four nozzlesare used to wind the wires onto such a core, as shown in FIG. 17,adjacent coil portions must share a slot along one side.

FIG. 17 is a diagram showing wires being simultaneously supplied to thecore from four nozzles of a winding device (not shown) having tworotational angles, 98.2 degrees and 81.8 degrees, as shown in FIG. 16,simultaneously forming a first coil portion A 108, a first coil portionB 109, a first coil portion C 110, and a first coil portion D 111,respectively.

The first coil portion A 108 in FIG. 17 is formed by winding a wiresupplied from a first nozzle, for example, ten or so turns around toothNo. 4 of the teeth 107 and tooth No. 22 of the teeth 107 which areseparated by four slots 102. The first coil portion B 109 is formed bywinding a wire supplied from a second nozzle, for example, ten or soturns around tooth No. 5 of the teeth 107 and tooth No. 9 of the teeth107 which are separated by four slots 102. The first coil portion C 110is formed by winding a wire supplied from a third nozzle, for example,ten or so turns around tooth No. 11 of the teeth 107 and tooth No. 15 ofthe teeth 107 which are separated by four slots 102. The first coilportion D 111 is formed by winding a wire supplied from a fourth nozzle,for example, ten or so turns around tooth No. 16 of the teeth 107 andtooth No. 20 of the teeth 107 which are separated by four slots 102.

In this case, the slot 102 between tooth No. 4 of the teeth 107 andtooth No. 5 of the teeth 107 is shared by a side portion of the firstcoil portion A 108 and a side portion of the first coil portion B 109,and the slot 102 between tooth No. 15 of the teeth 107 and tooth No. 16of the teeth 107 is shared by a side portion of the first coil portion C110 and a side portion of the first coil portion D 111.

For that reason, differences in impedance arise between the coilportions 108 to 111 in the slots 102 shared by the coil portions 108 to111 because the wires are wound under conditions in which the coilportions 108 to 111 interfere with each other, leading to the followingproblems:

Differences in induced voltage arise in the coil portions 108 to 111 andunbalanced currents flow through the brushes, and as a result, therectifying action of the brushes deteriorates, the temperature in thebrushes and the commutator increases together with the increase insparks generated by the brushes, the life of the brushes and thecommutator is reduced, torque ripples increase, and the operating noiseof the motor increases markedly due to the combined effects of theabove.

SUMMARY OF THE INVENTION

The present invention aims to solve the above problems and an object ofthe present invention is to provide an armature for a dynamo-electricmachine capable of preventing the occurrence of unbalanced currentsflowing through the brushes and of reducing operating noise whilemaintaining the rectifying effect of the brushes, and to provide amethod of manufacture therefor.

To this end, according to the present invention, there is provided anarmature for a dynamo-electric machine comprising: a shaft; a coresecured to the shaft having a plurality of slots extending in the axialdirection formed on the outer circumferential surface thereof; a coilcomposed of a plurality of coil portions formed by winding wires aplurality of turns around a pair of the slots separated by apredetermined number of the slots and offsetting each of the coilportions one slot at a time in the circumferential direction of thecore; and a commutator secured to the shaft having a plurality ofsegments; adjacent the coil portions sharing one of the slots along oneside thereof, wherein the segments which should have the same electricpotential are electrically connected by means of equalizing connectors.

According to another aspect of the present invention, there is providedan armature for a dynamo-electric machine comprising: a shaft; a coresecured to the shaft having a plurality of slots extending in the axialdirection formed on the outer circumferential surface thereof; a coilcomposed of a plurality of coil portions formed by winding wires aplurality of turns around a pair of the slots separated by apredetermined number of the slots and offsetting each of the coilportions one slot at a time in the circumferential direction of thecore; and a commutator secured to the shaft having a plurality ofsegments; the number of vacant slots between adjacent the coil portionsbeing nonuniform, wherein the segments which should have the sameelectric potential are electrically connected by means of equalizingconnectors.

According to another aspect of the present invention, there is providedan armature for a dynamo-electric machine comprising: a shaft; a coresecured to the shaft having a plurality of slots extending in the axialdirection formed on the outer circumferential surface thereof; a coilcomposed of a plurality of coil portions formed by winding wires aplurality of turns around a pair of the slots separated by apredetermined number of the slots and offsetting each of the coilportions one slot at a time in the circumferential direction of the corefor a plurality of laps; and a commutator secured to the shaft having aplurality of segments; the number of turns of the wires in the coilportions differing in the initial lap and the subsequent laps, whereinthe segments which should have the same electric potential areelectrically connected by means of equalizing connectors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a winding diagram for an armature according to Embodiment 1 ofthe present invention;

FIG. 2 is a diagram showing coil portions wound on a core during thewinding of wires by lap winding;

FIG. 3 is a diagram showing a coil wound on a core upon completion ofthe winding of wires by lap winding;

FIG. 4 is a winding diagram for an armature according to Embodiment 2 ofthe present invention;

FIG. 5 is a winding diagram for an armature according to Embodiment 3 ofthe present invention;

FIG. 6 is a diagram showing wires being wound by lap winding onto thecore in FIG. 5;

FIG. 7 is a diagram showing wires being wound by lap winding onto thecore in FIG. 5;

FIG. 8 is a diagram showing a coil body wound on the core in FIG. 5during the winding of wires by lap winding;

FIG. 9 is a diagram showing a coil wound on the core in FIG. 5 uponcompletion of the winding of wires by lap winding;

FIG. 10 is a diagram showing coil portions wound on the core of anarmature according to Embodiment 4 of the present invention during thewinding of wires by lap winding;

FIG. 11 is a side elevation of a conventional (but not prior art)armature;

FIG. 12 is a front elevation of the core in FIG. 11;

FIG. 13 is a diagram showing coil portions wound on the core in FIG. 12during the winding of wires by lap winding;

FIG. 14 is a diagram showing coil portions wound on the core in FIG. 12during the winding of wires by lap winding;

FIG. 15 is a diagram showing a coil wound on the core in FIG. 12 uponcompletion of the winding of wires by lap winding;

FIG. 16 is a front elevation showing another example of a core; and

FIG. 17 is a diagram showing wires being wound by lap winding onto thecore in FIG. 16.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

FIG. 1 is a winding diagram for an armature 100 of a motor which is adynamo-electric machine according to Embodiment 1 of the presentinvention and shows the winding of wires 103 onto a core 101 having fourpoles and twenty-two slots 102 using four nozzles of a winding device(not shown) simultaneously. The diagram shows the enamel-coated wires103 being wound by lap winding across a plurality of slots 102,simultaneously forming a first coil portion A 108, a first coil portionB 109, a first coil portion C 110, and a first coil portion D 111,respectively. A commutator 105 has twenty-two segments 104, segments 104which should have the same electric potential being electricallyconnected by means of equalizing connectors 106. For example, the firstsegment 104 is connected to the twelfth segment 104, the second segment104 is connected thirteenth segment 104, etc.

FIG. 2 is a diagram showing wires 103 being supplied from each of thenozzles of the winding device and wound onto the core 101 and shows theformation of a second coil portion A 112, a second coil portion B 113, asecond coil portion C 114, and a second coil portion D 115,respectively, after the engagement of hooks on the segments 104.Moreover, the initial formation of coil portions 108 to 111 on the core101 by wires 103 supplied from each of the nozzles is the same as inFIG. 17.

FIG. 3 is a front elevation of the armature 100 with a coil 116completely formed thereon by continuing to wind the wires 103 whileoffsetting one slot at a time.

In the armature 100 having the above construction, since segments 104which should have the same electric potential are electrically connectedby means of the equalizing connectors 106, although the wires are woundwith the side portions of adjacent coil portions 108 to 115 sharingslots 102 and the coil portions 108 to 115 interfering with each other,unbalanced currents do not flow through the brushes due to differencesin induced voltage arising in the coil portions. As a result,inconveniences such as the rectifying action of the brushesdeteriorating, the temperature in the brushes and the commutatorincreasing together with increases in sparks generated by the brushes,the life of the brushes and the commutator being reduced, torque ripplesincreasing, or the operating noise of the motor increasing markedly dueto the combined effects of the above, do not occur.

Embodiment 2

FIG. 4 is a winding diagram for an armature 300 of a motor according toEmbodiment 2 of the present invention and shows the winding of wires 103onto a core 101 having twenty-two slots 102 using three nozzles of awinding device (not shown) simultaneously. In this embodiment, wires 103are simultaneously supplied and wound onto the core 101 from a pluralityof nozzles of a winding machine whose number does not evenly divide thenumber of slots 102, giving rise to vacant slots A between adjacent coilportions 301, 302, 303. The number of vacant slots may be one or two andtheir distribution is nonuniform. In this case, the wires 103 are notwound uniformly onto the core 101 and there is a risk that differencesin induced voltages may occur between the coil portions 301, 302, 303.However, in this case also, the flowing of unbalanced currents throughthe brushes is prevented by electrically connecting segments whichshould have the same electric potential by means of equalizingconnectors.

Embodiment 3

FIG. 5 is a winding diagram for an armature 200 of a motor according toEmbodiment 3 of the present invention and shows wires 103 beingsimultaneously supplied from two nozzles of a winding device (notshown), simultaneously forming a first coil portion A 201 and a firstcoil portion B 202, respectively. Segments 104 which should have thesame electric potential are electrically connected by means ofequalizing connectors 106. For example, the first segment 104 isconnected to the twelfth segment 104, the second segment 104 isconnected thirteenth segment 104, etc. FIG. 6 is a front elevation ofthe core 101 at that time.

FIG. 7 is a diagram showing wires 103 continuing to be supplied from thetwo nozzles and shows the additional formation of a second coil portionA 203 and a second coil portion B 204, respectively, after theengagement of hooks on the segments 104.

FIG. 8 is a front elevation of the core 101 with a coil body 205 formedthereon by continuing to wind the wires 103 for a total of eleven slotswhile offsetting one slot at a time. FIG. 9 shows the formation of acoil 206 upon completion of a winding in which the wires 103 in the coreportion up to the point in FIG. 8 were wound, for example, six turns,and after that were wound, for example, seven turns.

By making six turns of the wires 103 in the initial lap and seven in thesubsequent laps in this manner, the wires 103 have the equivalent of 6.5turns, facilitating the modification of motor performance and increasingthe degree of design freedom. There is a risk that in this conditiondifferences in impedance between the coil portions may arise due to thedifferences in the number of turns of the wires 103, and unbalancedcurrents may flow through the brushes due to differences in inducedvoltage arising in the coil portions. However, in this embodiment, aswith Embodiments 1 and 2, since segments 104 which should have the sameelectric potential are electrically connected by means of the equalizingconnectors 106, unbalanced currents do not flow through the brushes.

Embodiment 4

FIG. 10 is a diagram showing a case in which the wires 103 are woundseven turns in the initial lap. In this case the shaded portions E ofthe slots 102 are completely covered by a first coil portion A 211 and afirst coil portion B 212, and the area of the shaded portions E isgreater than in Embodiment 3 (see FIG. 6). As a result, thecross-sectional area of the slots 102 is reduced and windability is lessfavorable than in Embodiment 3, but by winding more turns in the initiallap when the diameter of the coil portions is small and winding lessturns in the subsequent laps when the diameter of the coil portions islarge, the difference in impedance between the initial lap and thesubsequent laps is reduced.

Each of the above embodiments of the present invention has beenexplained using a motor as an example of a dynamo-electric machine, butthe present invention can also be applied to a generator. Furthermore,the number of equalizing connectors 106 in each of the embodiments iseleven, but of course they are not limited to this number.

As explained above, the armature for a dynamo-electric machine accordingto one aspect of the present invention comprises: a shaft; a coresecured to the shaft having a plurality of slots extending in the axialdirection formed on the outer circumferential surface thereof; a coilcomposed of a plurality of coil portions formed by winding wires aplurality of turns around a pair of the slots separated by apredetermined number of the slots and offsetting each of the coilportions one slot at a time in the circumferential direction of thecore; and a commutator secured to the shaft having a plurality ofsegments; adjacent the coil portions sharing one of the slots along oneside thereof, wherein the segments which should have the same electricpotential are electrically connected by means of equalizing connectors.Therefore, operating noise can be reduced while maintaining theperformance of the dynamo-electric machine and the rectifying effect ofthe brushes.

According to another aspect of the present invention, the armature for adynamo-electric machine comprises: a shaft; a core secured to the shafthaving a plurality of slots extending in the axial direction formed onthe outer circumferential surface thereof; a coil composed of aplurality of coil portions formed by winding wires a plurality of turnsaround a pair of slots separated by a predetermined number of the slotsand offsetting each of the coil portions one slot at a time in thecircumferential direction of the core; and a commutator secured to theshaft having a plurality of segments; the number of vacant slots betweenadjacent the coil portions being nonuniform, wherein the segments whichshould have the same electric potential are electrically connected bymeans of equalizing connectors. Therefore, operating noise can bereduced while maintaining the performance of the dynamo-electric machineand the rectifying effect of the brushes.

According to still another aspect of the present invention, the armaturefor a dynamo-electric machine comprises: a shaft; a core secured to theshaft having a plurality of slots extending in the axial directionformed on the outer circumferential surface thereof; a coil composed ofa plurality of coil portions formed by winding wires a plurality ofturns around a pair of the slots separated by a predetermined number ofthe slots and offsetting each of the coil portions one slot at a time inthe circumferential direction of the core for a plurality of laps; and acommutator secured to the shaft having a plurality of segments; thenumber of turns of the wires in the coil portions differing in theinitial lap and the subsequent laps, wherein the segments which shouldhave the same electric potential are electrically connected by means ofequalizing connectors. Therefore, operating noise can be reduced whilemaintaining the performance of the dynamo-electric machine and therectifying effect of the brushes.

According to one form of the armature for a dynamo-electric machine, thenumber of turns of the wires in the coil portions in the initial lap maybe less than the number of turns of the wires in the coil portions inthe subsequent laps. Therefore, the modification of torque andrevolution performance can be facilitated and the degree of designfreedom of the dynamo-electric machine increased, while maintaining therectifying effect of the brushes and with the operating noise reduced,even when the number of turns of the wires in the coil portions in theinitial lap is less than the number of turns of the wires in the coilportions in the subsequent laps.

According to another form of the armature for a dynamo-electric machine,the number of turns of the wires in the coil portions in the initial lapmay be greater than the number of turns of the wires in the coilportions in the subsequent laps. Therefore, differences in impedancebetween the coil portions in the initial lap and the coil portions inthe subsequent laps are small even when the number of turns of the wiresin the coil portions in the initial lap is greater than the number ofturns of the wires in the coil portions in the subsequent laps, enablingoperating noise to be reduced while maintaining the performance of thedynamo-electric machine and the rectifying effect of the brushes.

1. A method for manufacturing an armature for a dynamo-electric machinecomprising: securing a core to a shaft, wherein said core has aplurality of slots extending in an axial direction formed on an outercircumferential surface of said core; winding a coil on said corecomprising the steps of: simultaneously winding a first plurality ofcoil portions on said core to form a first simultaneously-wound coilportion group; simultaneously winding a second plurality of coilportions on said core to form a second simultaneously-wound coil portiongroup, wherein said second plurality of coil portions of said secondsimultaneously-wound coil portion group are wound to be offset in thecircumferential direction of said core from said first plurality of coilportions of said first simultaneously-wound coil portion group; whereinsaid first and second pluralities of coil portions are formed by lapwinding wires a plurality of turns around a pair of said slots separatedby a predetermined number of said slots, wherein said first and secondsimultaneously-wound coil portion groups are consecutively-wound groups,and wherein a number of vacant slots between adjacent ones of said coilportions within each of said simultaneously-wound coil portion groups isnonuniform; securing a commutator to said shaft, said commutatorcomprising a plurality of segments; and permanently electricallyconnecting pairs of said segments that should have the same electricpotential with a plurality of equalizing connectors, so that each ofpairs of said coil portions that should have the same electric potentialhas a substantially equal electrical potential, wherein each of saidpairs of said segments is connected by a single equalizing connector ofsaid plurality of equalizing connectors, and wherein each of said coilportions has a starting end connected to a first segment of saidcommutator and a finishing end connected to a second segment of saidcommutator, and said first segment is adjacent to said second segment.